Organization: Department of Interior (DOI)

Research Title: Biogeochemical Exchanges between Terrestrial Systems

Funding Level (millions of dollars):

FY94	2.7
FY95	2.6
FY96	2.6

Committee on Environment and Natural Resources (CENR) Component:
(a) Subcommittee: Global Change Subcommittee (100%)
(b) Environmental Issue: Large-scale change in land use 80%; Climate Change 20%
(c) Research Activity: System structure and function: Observations, Prediction, Data Management

Organizational Component:
U.S. Geological Survey
104 National Center
Reston, VA 22092

Point of Contact: :
Michael Carr
Phone: 703-648-4408

Research Goals:
A critical aspect of predicting future atmospheric concentrations of natural greenhouse gases relates to understanding the sources and sinks of these gases in terrestrial environments.

Research Description:
The USGS conducts research on the global carbon and nutrient cycles, past and present, to improve understanding of the sources, sinks and exchanges of carbon over time under different climatic regimes. Many of the pathways for carbon (as well as nitrogen and phosphorus which are the major nutrients that control CO ₂ uptake) are associated with water fluxes that are a major topic of USGS global change research. Thus, it is logical and efficient to conduct research on the pathways of these gases in conjunction with ongoing USGS studies of the hydrologic cycle. Moreover, other terrestrial events such as volcanic eruptions often have significant effects on the global energy balance and, thereby, complicate interpretation of natural and anthropogenic contributions to global change. The Bureau of Mines also conducts research on the contribution of coal mining to atmospheric methane concentrations. This research has lead to enhanced understanding of methane mitigation and mining emissions.

The program emphasizes two primary topics: (1) Improving the understanding of the sources and sinks of carbon dioxide and methane, especially in soils, lakes, wetlands, the unsaturated zone, volcano emissions, and in areas of active and abandoned coal mining. The role of terrestrial ecosystems in sequestering atmospheric carbon dioxide is a major unknown in greenhouse effect predictions. An effort will be made to develop and deploy measurement technology that can help quantify the role of terrestrial systems in the carbon budget. The program also includes development of time- dependent models of the global carbon cycle that focus on the feedbacks between climate and the rates of exchange of greenhouse gases among the various reservoirs, and the subsequent changes in greenhouse gas concentrations. (2) Investigating the flux of carbon, gaseous volatiles and aerosols between terrestrial, atmospheric, and marine environments through contemporaneous observations (e.g., monitoring volcanic emissions, real- time monitoring of coal bed methane emissions) and evidence preserved in the geologic record. Emphasis will be given to understanding the links between the carbon cycle and those of other elements (e.g., phosphorus, nitrogen, and sulfur).

Program Interfaces:
This program is designed to facilitate collaboration with researchers involved in long-term ecological and nutrient studies (such as being conducted at LTER and Biosphere Reserves) and researching, monitoring, and modeling greenhouse gas emissions. Partnerships and agreements are in place between Department of the Interior bureaus and with the Department of Energy, U.S. Forest Service, Environmental Protection Agency, National Aeronautics and Space Administration, and numerous universities.

Program Milestones:

Policy Payoffs:
Improved understanding and documentation of current terrestrial carbon sources, sinks, and fluxes will help balance the modern global carbon budget. Improved understanding of modern processes when combined with information on changes of sources and sinks under different climates will improve estimates of future atmospheric greenhouse gas concentrations.